function print_power_sets($arr)
{
echo "POWER SET of [" . join(", ", $arr) . "]<br>";
foreach (power_set($arr) as $subset) {
print_array($subset);
}
}
function power_set($array){
if(!$array) return array($array);
$a = array();
foreach( power_set( array_slice( $array, 1) ) as $i ){
$return[] = $i;
$return[] = array_merge( array( $array[0] ), $i);
}
return $return;
}
function power_perms($arr)
{
$power_set = power_set($arr);
$result = array();
foreach ($power_set as $set) {
$perms = perms($set);
$result = array_merge($result, $perms);
}
return $result;
}